After reviewing AI tools for a long time, I’ve found that it’s not that people don’t know how to use them—it’s that all kinds of “error messages” make them lose their minds: wrong key, insufficient permissions, flaky network, or suddenly getting rate-limited. Below is a “copy-and-follow” checklist organized by product, summarizing frequent issues and the fixes I commonly use.
For ChatGPT, the most common errors are API keys and risk controls
Typical messages: API key invalid, 429 too many requests, access restricted.
- Make sure you pasted the key correctly: Don’t include spaces; don’t mix up a project key with an account key; generating a new key is the quickest fix.
- Don’t brute-force 429: Reduce concurrency, add retries and backoff; for long conversations, remember to summarize—otherwise tokens keep piling up and get expensive.
- Access restricted: Usually it’s an unstable network/region/node; switching to a stable route is more useful than repeatedly refreshing.
Claude is more likely to be blocked by permissions and quotas
Typical messages: 401/403, insufficient permissions, quota exhausted. Claude is quite sensitive to “organization/project/permissions”; a common pitfall is putting the key in the wrong environment or not enabling all needed permissions.
- Check permissions: Whether the key belongs to the current project, and whether model access is enabled.
- Don’t treat prompts like a blind box: If you want stable output, clearly specify the goal, format, and boundaries—the improvement is immediate.
Gemini commonly runs into 403 and region-related restrictions
When Gemini throws a 403, I usually suspect two things first: a “dirty” network egress, or the service not being enabled in the console.
